In the treatment of some diseases or defects associated with a patient, it has been found necessary to access specific targets within the patient. For example, in neurosurgery, it have been found necessary to access specific targets within the patient's brain. In neurosurgery, the specific targets are typically located and identified by one of a number of techniques. Sometimes the target can be visualized on computer tomography (CT) or magnetic resonance imaging (MRI). Other times, the position of the target must be determined by its relationship to an anatomic structure viewable on scanning using conventional radiographs or by ventriculography.
Once a target has been identified, neurosurgery involves making a drill hole in the relatively thick bony structure surrounding the brain (i.e., the skull). The drill hole is made by a surgeon at a desired entry point using a surgical drill. The surgeon then guides (e.g., using trajectory guide tubes) one or more surgical instruments or observation tools (e.g., electrodes—recording or stimulating, cannulas, needles, biopsy instruments, catheters or other types of probes or devices) through the entry hole to the specific targets within the brain. Based on the fact that, to some extent, considerable relative movements between the instruments or tools and the targeted positions on the body of the patient can occur with hand-guided instruments or tools, and that these relative movements are in part associated with considerable risks for the patient (e.g., damage to healthy brain tissue), it is desirable to anchor these instruments or tools securely relative to the body while still being able to guide them in three dimensions within certain limits. To prevent relative movements between the body of the patient and the surgical instruments or observation tools, a drive and trajectory guide assembly mechanically coupled to the patient may be utilized.
Using a secured drive and trajectory guide assembly, and in some examples, one or more guide tubes, the instruments or tools may be precisely advanced into the brain until the operable portion of each of the instruments or tools is positioned adjacent the site of interest (i.e., the site of the brain to be operated on). Once the operable portion of each instrument or tool is positioned as desired, or during the advancement of each instrument or tool, selective position retainment of such instruments or tools is often needed. In addition, selective positions of the guide tubes may need to be retained.
Unfortunately, many of the currently available assemblies used to guide or retain neurosurgical instruments, observations tools, or guide tubes have one or more of the following drawbacks: being expensive to manufacture (e.g., due to precise tolerance requirements); retaining a limited number of instruments, tools, or tubes; requiring actuation at multiple sites; requiring a relatively large clamping force be applied to one or more actuators; or not providing a user with a good “feel” of the actual retainment force being applied to each instrument, tool, or tube (e.g., due to large bending or compression forces required for retainment).
It is with this knowledge of the foregoing state of the technology that the present multiple instrument retaining assembly and methods therefor have been conceived and are now set forth in text and drawings associated with this patent document.